* Introduce framework for running basic tests for entities
* Add pipeline tests to CircleCI config
* Make pipeline tests more configurable and fix CircleCI config
* Add coverage dir to pipeline package
* Add basic tests for all exchange event entities
* Add tests for remaining entities
* Create separate test scripts in package.json and add new info to README
* Update db_setup.ts to revert migrations even if you are using docker
* Automatically pull the postgres image if needed
* Add comment about why NumberToBigIntTransformer is needed
